Note 5 - Investments, Available-for-sale - Summary of Investment Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Amortized Cost		$ 3,981
Unrealized Gain		0
Unrealized Loss		(10)
Fair Value	$ 0	3,971
Short-term investments	$ 0	3,971
Corporate Debt Securities [Member]
Amortized Cost		3,981
Unrealized Gain		0
Unrealized Loss		(10)
Fair Value		3,971
Short-term investments		$ 3,971